Interactive speed limiters

[Ancient]

...
EDIT: Actually it is available free - though you need to register on TRL's website:

http://www.trl.co.uk/reports-publicatio ... ortid=2542

Thanks for the link. I have only had time so far to read the Executive Summary and Introduction alongside my day job, but so far it seems up to par for this type of document, produced from the vested interests of proponents of current 'road safety' convention.
My initial reactions:

Road Casualty reduction targets obviously measure casualties (however defined*); they do not measure hoe safe the roads are to use by other than 'traffic' (which by implication and most measurements, means motor traffic). This is the problem with "a casualty reduction target": The simplest and most effective means of achieving this is to give vast areas of public space over to motor vehicles (suitably protecting their occupants) and keep everyone else away behind fences and walls. This ignores the actual damage to communities which this (commonly practised) method incurs.

*Defined here as Killed, seriously Injured and slightly injured. There are problems with all of these casualties. Being based on Police reports, the difference between Serious and Slight is made by unqualified personnel with (usually) no real medical training. 'Slight' bruising can mask deadly injury, slight cuts appear serious to untrained people, there is no standardisation in the data. Killed on the roads seems clear enough, but only applies to those who die of their injuries within 30 days of the incident. Improvements in trauma care have huge and un-accounted effects on this. Statistical analysis of such uncontrolled inputs risks GIGO effects.

"It identified factors which would influence the number of casualties, such as an increase in the elderly population and rising levels of car ownership. There were three priority concerns: protection of vulnerable road users, reconciling the demand for movement with the need for safety and reducing the chances of human error leading to accidents."
No mention of demand for space other than for "movement": People legitimately (used to) use streets for social interaction.

"a method which has proved successful in forecasting casualties in Great Britain. This is based on the long-term relation between the annual volume of motor traffic in the country and the number of casualties"
Assuming other human behaviour remains constant and people don't simply learn ("There is education even in the lower animals" said MOORE-BRABAZON opposing licences for motor drivers) to keep out of the way of the motorised user.; although it does acknowledge "for the outcome will depend upon the future behaviour of travellers and the growth of road travel as well as the means used to promote safe travel" - again the assumption of road=travel. In effect, "promote safe travel" means "promote car use"(don't walk, it's dangerous; don't cycle here, it's dangerous) which is (perhaps counter-intuitively) bad for driving enthusiasts such as the members here, as it promotes congestion.

Edit to add: "The casualty rate is defined as the number of casualties of a specific severity per billion vehicle-km of motor traffic." speaks for itself (hopefully).

[Ancient]

Because human reaction times have not improved.
Define "vehicle safety". What evidence do you have that it has improved?

Surprised this is a serious question, but in addition to what has been provided already, Google is your friend, such as this from the US DoT:

http://www-nrd.nhtsa.dot.gov/Pubs/811572.pdf

"Our study finds remarkable improvements to vehicle safety...The nationwide impact of these advancements is substantial. We estimate that improvements made after the model year 2000 fleet prevented the crashes of 700,000 vehicles; prevented or mitigated the injuries of 1 million occupants; and saved 2,000 lives in the 2008 calendar year alone. Of the 9 million passenger vehicles that were in crashes, the crashes of an estimated 200,000 of them were preventable by improvements to the model year 2008 fleet, and the injuries of 300,000 of their 12 million occupants would have been prevented or mitigated, including saving 600 lives."

A perfectly serious question actually. Who is made safer? To do what? When they do, who (usually a different person) is put at increased risk?

Again, your evidence is biased towards saving of vehicle occupants. When vehicle occupants are made "safer", can you guess what that does to the behaviour of vehicle drivers? Clue: your initial assumption which I questioned: That speed limits were out of date because vehicles have "improved" is a perfect example of this type of behaviour - a behaviour pattern conveniently ignored by the 'road safety' establishment, even when the predicted 'advantages' of seat belt legislation (justified by exactly this type of report) proved elusive.

[martine]

...a behaviour pattern conveniently ignored by the 'road safety' establishment, even when the predicted 'advantages' of seat belt legislation (justified by exactly this type of report) proved elusive.

Are you saying that seat belt wearers feel safer and therefore take greater risks? This may be true but it is still overwhelmingly safer to wear one than not...

http://www.roadsafetyobservatory.com/HowEffective/vehicles/seat-belts

Ditto motorway speed limits - our cars are hugely safer both passive and actively than they were in the 60s when the 70 limit was introduced. Sure some people may take extra risks but the KSI rates are but a fraction of what there were even though many more passenger/miles are being driven per year.

Same applies if you isolate cycling KSIs...
here

Most of Europe agree the motorway limit should be 80 as well.

[Ancient]

...a behaviour pattern conveniently ignored by the 'road safety' establishment, even when the predicted 'advantages' of seat belt legislation (justified by exactly this type of report) proved elusive.

Are you saying that seat belt wearers feel safer and therefore take greater risks? This may be true but it is still overwhelmingly safer to wear one than not...

http://www.roadsafetyobservatory.com/HowEffective/vehicles/seat-belts

Ditto motorway speed limits - our cars are hugely safer both passive and actively than they were in the 60s when the 70 limit was introduced. Sure some people may take extra risks but the KSI rates are but a fraction of what there were even though many more passenger/miles are being driven per year.

Same applies if you isolate cycling KSIs...
here

Most of Europe agree the motorway limit should be 80 as well.

I;m agreeing with this statement (apart from "may be" - there is sufficient evidence of risk compensation to be sure it occurs). Those risks taken do not necesarilly translate into KSIs for drivers, which is why I asked "Who is made safer? To do what? When they do, who (usually a different person) is put at increased risk?"
Germany allows coaches to travel at higher speeds if all passenger seats have seatbelts: Risk compensation enshrined in law: Does that make it a Good Thing? Why is it considered OK to travel faster if the passengers are belted up? Because they are safer if it crashes. Who else's risk is increased by that increased speed?

[trashbat]

Well I'm amazed that anyone could manage even 56mph on the A31 during the Boat Show, never mind double that figure.

[revian]

So everyone who drives a BMW or Audi is a prat?

If you said that, you would be wrong, but only a little bit (based on my experience).

Might we know what you drive Graham? Then we could give you a wild and insulting description to match....

Is it that you just can't keep up with us?

[michael769]

A perfectly serious question actually. Who is made safer?

Everybody. It's not just vehicle occupant protection that has improved. Pedestrian protection (which also benefits cyclists) has also improved massively.

Those risks taken do not necesarilly translate into KSIs for drivers

I think you seem to be approaching this from the premise that vehicle safety only benefits drivers.

This premise is quite flawed. Considerable effort has been invested in pedestrian protection too. Today the chances of dying after being hit by a car travelling at 30mph is only 7%. In the 1970s by some analysis it was 55%).

Have a look at Crandall or for a UK perspective McCarthy on what is and continues to be done.

To do what?

To use the roads. OK a flippant answer but I am not sure the point of this question. The purpose of vehicle safety engineering is to mitigate (and soon prevent) the consequences of when we fallible humans get it wrong on our roads.

When they do, who (usually a different person) is put at increased risk?

No one. Our day to day activities include a degree of inherent risk. Everything we do has some agree of risk.

But just because a level of risk is that of normal day to day activities does not mean that we should not seek to reduce it if can be done in a proportionate manner.

Road Safety Engineering is not about preventing additional risk, it is about reducing existing risks and harm.

[Graham Wright]

Might we know what you drive Graham? Then we could give you a wild and insulting description to match....

Is it that you just can't keep up with us? [/quote]

I drive a 940 Volvo LPT estate - an old one, N registered with approaching 300,000 miles on the clock. Driving to my mother's death bed, it achieved well over 120. Apart from that, I drive within the legal limit and am still "progressive". From time to time, I also drive a Lenham Sports 3.5 litre V8 MGB. May I ask what you drive?

I am disappointed to learn implicitly from this thread that excessive speeds seem to be acceptable.

My comments on Audi drivers are based on my own experience. If I see a rapidly approaching car in my mirrors, I anticipate an Audi, BMW or Mercedes. More likely than not, I am then tailgated and bullied to move over and let them pass. To do so, I would need to exceed the speed limit. Leaving a gap between me and the overtaken car before pulling in, I am further hassled. Having passed, they will then accelerate hard until they reach their next victim. The frequency of braking (as evidenced by brake lights) I find baffling.

The A31 turns into the M27 which is where I have observed the (estimated) 80,90 and 100.

The law on speeds seems to me to be irrelevant as it seems not to be policed. During our week, we saw neither a stopped vehicle nor, indeed, a police car on that road.

My opinions are based not only on speeding, but general aggressive driving. My route home from work entails a turn right into a minor road from a 50 limit. There is roughly 1/4 mile visibility before that turn. On two occasions, I have been overtaken during my turn both times by Audis. The second time caused damage to the hedge (and presumably the Audi which did not stop). Despite the advice from Roadcraft, I always indicate well before that turn even if no following traffic is visible in my mirrors. Due to the short range rearwards, the presence of oncoming traffic and the speed of the car behind, in both cases my turn was initiated with a clear road in the mirrors.

Another frequent example is undertaking. This seems to be the province of the BMWs. When tailgating seems not to be effective, the solution seems to be to switch to an inside lane, undertake and then rejoin the original lane. One car length gained - only another 100 to go.

Another one is push, push, push, tailgate, overtake and then turn left. How puerile.

The general ethos on the roads seems to be "gotta go faster". Why? Please someone explain the benefit. On motorways there is a possibility of a shorter journey. A 100 mile journey at a constant 100 mph would take one hour (I think I am fairly safe in that equation!). At 70 mph, it would take an hour and 25 minutes (please check!). Both these figures assume clear runs. The downside is fuel consumption, general wear, pollution, increased stress levels and aggravation to other motorists. Now; what to do with those 25 minutes?

In conclusion, is it safe for me to assume from the responses that speeding is ok and I should not be concerned? For the record, the most difficult lesson I learned from the IAM was coping with restraint. I now react no more than muttering "Prat" and more often than not, just think it.

I take pride in being able to drive legally and wonder what those who do not, feel necessary to prove.

[Graham Wright]

Is it that you just can't keep up with us?

Not many vehicles cannot achieve 70 mph.

[Ancient]

No one. Our day to day activities include a degree of inherent risk. Everything we do has some agree of risk.

But just because a level of risk is that of normal day to day activities does not mean that we should not seek to reduce it if can be done in a proportionate manner.

Road Safety Engineering is not about preventing additional risk, it is about reducing existing risks and harm.

I'm sorry but you are wrong; risk to others does increase.
It's quite simple, if you look at how roads were used before motor vehicles came to dominate them, they were social interactive places. Pedestrian safety has improve because pedestrians have learned to keep off the roads (the attitude in society now is that roads belong to cars: Precisely what Churchill said we should avoid!).
Breaking someone's leg and throwing them into the air instead of breaking their hip is not improved safety, it is mitigated damage.
The attitude of most drivers (and some here) is that improvements in vehicle control, protection and collision mitigation should mean that cars are allowed to go faster (that the speed limits are outdated because of these improvements): This behaviour (known as risk compensation) uses up any improvements in safety and increases risk to others. Seatbelt laws did not provide the reduction in road casualties predicted, but pedestrian and cycling casualties stopped falling as fast as they had been (i.e. more were injured by motor vehicles than would have been).
Motor vehicle casualties have been falling steadilly since 1949, largely because people have altered their behaviour to cope. The downside is reduced socialisation in the street (less social cohesion) and (the one we are literally paying for) reduced exercise as car travel increases over non-motorised travel.

[Slink_Pink]

[quote="Ancient]...Breaking someone's leg and throwing them into the air instead of breaking their hip is not improved safety, it is mitigated damage...[/quote]Depends how you define "safety" - it's a relative term. Without medical training, I am not in a position to judge whether it's safer to have a hip broken or a leg broken + free air miles... I know which I'd prefer though.

[jcochrane]

The attitude of most drivers (and some here) is that improvements in vehicle control, protection and collision mitigation should mean that cars are allowed to go faster (that the speed limits are outdated because of these improvements)

Maybe I have misunderstood you, and apologies if I have, but your experience appears to differ from mine. What I have constantly come across here and elsewhere is that driving at a posted speed limit does not make that speed safe. Which is something completely different.

From my experience of response drives in police area cars in the Met. (therefore subject to 30mph limits) speeds up to 90/100 were not uncommon but safely done.

A few days ago I drove out of an NSL into a lower limit. Don't know what it was could be 30 as there were no repeater signs. Drove through this section at speeds varying between 15mph and 60mph, fast sections for enthusiastic progress and a number of dodgy (fun) bends. Alongside me was a serving advanced police traffic officer from the Met.

His comments was that there was no way that I could have known of the limit change as the discs were completely covered in foliage but he was highly impressed with the rapid and at all times 100% safe progress displayed showing a high level of awareness of everything around and consistently matching speed to vision.

I am not making a case opposing your statement but that it is the choice of speed that makes it safe or not. Note that at times I brought speed down to 15mph, well below any posted limit.

[TheInsanity1234]

I think speed limits should be lowered from 30 to 20 in most pedestrianised areas, but to compensate, speed limits on motorways and rural roads (i.e. a large majority of A and B roads) should be abolished altogether, except for areas where there is a genuine need to lower traffic speed, such as the New Forest National Park (because of unfenced roads with roaming wildlife).

My reasoning behind this is that, if we use speed limits sparingly, then people will actually take note of them and travel within the speed limit because they will know that there is a increased hazard when maintaining higher speeds.

This is why I think so many people speed on the motorways and around urban areas, because there are so many speed limits for so many different scenarios, and quite a lot of them are completely pointless. As a result, people will have become fed up with travelling at a lower speed when there is no obvious reason, so they will drive as fast as they wish.

There is a perfect example in the case of the B4000 passing along the top of the Lambourn Valley in Berkshire. It has a limit of 50 mph for the whole stretch between the M4 turn off and the point where it goes from Berkshire into Wiltshire. I've seen a lot of people travelling at 60 mph (and higher speeds have been seen too) along it quite safely, and the speed limit is just entirely pointless for the large part of it, which suggests that a lot of people speed because they've become oblivious to the ever increasing number of lower limits.

[jlsmith]

If you look at how roads were used before motor vehicles came to dominate them, they were social interactive places... The attitude of most drivers (and some here) is that improvements in vehicle control, protection and collision mitigation should mean that cars are allowed to go faster (that the speed limits are outdated because of these improvements): This behaviour (known as risk compensation) uses up any improvements in safety and increases risk to others...The downside is reduced socialisation in the street (less social cohesion) and (the one we are literally paying for) reduced exercise as car travel increases over non-motorised travel.

Risk compensation is a fact of life, and even assuming there is a direct correlation between downward marginal increments in mph and safety (something think has only been assumed on this thread as a truism rather than argued cogently) it is in play as much as when you choose to drive at the speed limit of 70mph instead of 60mph as when our appalling friends in their Audis drive 80mph instead of 70mph.

I also think you are wearing your rose tinted spectacles in respect of how roads used to be. I am reading a social history of England at the moment, and during many periods of history the main social interaction when on English roads outside of towns came from the highwayman. In later times the level of road deaths was the same, if not higher, than now, despite far fewer journeys.

Arguments relating to social cohesion and lack of exercise may have their place (though not, I respectfully suggest, here) as they have nothing to do with evaluating the 70mph speed limit.

[revian]

Might we know what you drive Graham? Then we could give you a wild and insulting description to match....

Is it that you just can't keep up with us?

I drive a 940 Volvo LPT estate - an old one, N registered with approaching 300,000 miles on the clock. Driving to my mother's death bed, it achieved well over 120. Apart from that, I drive within the legal limit and am still "progressive". From time to time, I also drive a Lenham Sports 3.5 litre V8 MGB. May I ask what you drive?

Can't you guess? Black BMW318d... Usually within the speed limit. The last time I deliberately allowed my self to exceed it on a long journey was for the same 'parent' reason as you.... But nowhere near your 'excess'. It was in my previous car..FordFocus 1.8tdi. Whether it was sensible fir either of us to do this at an emotionally sensitive time.....?

You volvo driving cloth capped pipe smokers

My own experience is that any old mongrel car will undertake/tailgate/ drive like an idiot...I'm in the Wirral for a few days where the jumping of red traffic lights seems ingrained... Though I couldnt pick specific makes out